📜  门| GATE CS 2008 |第45章

📅  最后修改于: 2021-06-29 00:56:02             🧑  作者: Mango

从下图中的顶点a运行时,Dijkstra的单源最短路径算法可计算到的正确最短路径距离

(A)仅顶点
(B)仅顶点a,e,f,g,h
(C)仅顶点a,b,c,d
(D)所有顶点答案: (D)
说明: Dijkstra的单源最短路径不能保证适用于负负边的图形,但它适用于给定的图形。
让我们来看看…

Let us run the 1st pass
b 1
b is minimum, so shortest distance to b is 1.

After 1st  pass, distances are
c 3, e -2.  
e is minimum, so shortest distance to e is -2

After 2nd pass, distances are
c 3, f 0.  
f is minimum, so shortest distance to f is 0

After 3rd pass, distances are
c 3, g 3.  
Both are same, let us take g. so shortest distance to g is 3.

After 4th pass, distances are
c 3, h 5  
c is minimum, so shortest distance to c is 3

After 5th pass, distances are
h  -2
h is minimum, so shortest distance to h is -2

这个问题的测验